core/minute-ia: Add __ram_free to link script
core/minute-ia: Add __ram_free to link script

Use __ram_free instead of defining a fake FLASH region in the
linker script.

This reverts commit 6fd1d521e48
("core/minute-ia: Add FLASH memory configuration").

BRANCH=none
BUG=b:123327630
TEST=make BOARD=atlas_ish -j shows
     *** 592328 bytes in RAM still available on atlas_ish ****

Change-Id: Iacce7924dd867024e5381e31f1afb12d13305f3a
Signed-off-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1496686
Reviewed-by: Patrick Georgi <bc411205f21846a74924ee7b489c75617ec76078@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec